Chicagoland MG Club: Driveline January-February 2011
Technical Stuff

The following is an excerpt from “Tech Tips” section of the Chicagoland MG Club website.

  • A good screw-in compression tester is a must. If the compression is bad, a tune-up is a waste of time.

  • A good electrical multi-meter will save a lot of aggravation in finding ignition and charging problems.

  • A 12-volt test light is needed for any electrical troubleshooting.

  • The nuts on the SU carburetor linkages need a 2 BA wrench. A 5/16” is almost right, but it can be frustrating. Note: The BA (“British Association") wrench is for the thread range, rather than BSF or BSW. Further information on the BA and other British thread types can be found at:

  • Brake hose fittings are British so a selection of British wrenches will help.

  • A steering wheel nut is 1-1/8” and most tool kits don’t have this large a size.

  • The engine crank nut and front hub nut are 1-5/16” and the rear hub nut is 1-7/8”.

  • Doing carburetor work without a Unisyn or similar tool is just an exercise in frustration. Unless you are an expert, comparing the hiss will not get the carburetors in sync.


    `The following are excerpts from University Motors Limited website ( dealing with gasoline and additives for our cars.

    Affects of Ethanol

    : I am a long time owner of many MGBs and my current one is a '65 tourer. I'm writing to seek your advice on the effects of ethanol in gasoline on MGBs.
    I usually add an octane booster and dry gas once or twice a year to my fuel. My present MGB isn't my daily driver but I use it quite regularly on clear, dry days, year-around, so the fuel is "changed" on a consistent basis. As I'm sure you are aware, parts of the country have started using the 10% ethanol mixture in the local gasoline.
    I've been reading on the web some disconcerting comments about how the ethanol mixture will be a problem for older cars that have carburetors, rubber seals, and hoses. What do you think?

    : Of course, ethanol does not contain the same number of BTU's, gallon for gallon, as does "real" gasoline. But so far the only problem that we've encountered with our MGs is the gross expansion of rubber gaskets. Fortunately, there are not many of these within the fuel system. There are some rubber gaskets inside the fuel pump, but they've not been a problem at all. The rubber O ring that seals the sending unit against the tank on the MGB has not been a problem. The only snags we've hit are with the aftermarket rubber sending unit gaskets for the T type, MGA, and early MGB.

    So, as far as it goes right now, we've seen no downside (except mileage) to the addition of ethanol to the gasoline.


    : I cannot find lead additive in my area for my '73 and '77 MGB. I tried all the regular auto parts stores in my area. Do you have lead additive for sale??

    : No need to waste your money on mystery cans. Simply use 89 octane. Someday, you will burn out your exhaust valves -- usually number three exhaust. At that time be certain to have installed:
    hardened seats, bronze-silicone guides and umbrella seals. The 1977 was designed to run on unleaded; the 1973 will run just fine too! My 1973 MGB/GT has used 89 octane for the past fifteen years.

    — John Twist - University Motors, LTD

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